1. Field of the Invention
The invention relates to a driving circuit, and more particularly to a driving device for a scan driving device of a display panel.
2. Description of the Related Art
FIG. 1 shows a scan driving device in a conventional display panel. Referring to FIG. 1, a scan driving device 1 outputs driving signals S1-SN (N is a positive integer) and transmits the driving signals S1-SN to a display array of the display panel through scan lines. The scan driving device 1 comprises a plurality stages of shift registering units 101-10N and a plurality of buffering output units 111-11N. Each of the shift registering units 101-10N comprises switch units 100 and 101 and inverter units 102 and 103, and the switch unit 100 receives a start signal. The shift registering units 101-10N generate shift registering signals VSR1-VSRN respectively, and the shift registering signals VSR1-VSRN are sequentially asserted. Except for the shift registering signal VSRN, generated by the shift registering unit 10N, the shift registering signals VSR1-VSRN−1 generated by the shift registering units 101-10N−1 serve as the start signals of a next shift registering units 102-10N, respectively. The start signal of the shift registering signal VSR1 is input by a specific circuit.
The buffering output units 111-11N respectively receive the shift registering signals VSR1-VSRN. Each of the buffering output units 111-11N comprises a logic gate 110 and buffer 111. For each buffering output unit, the logic gate 110 receives the respective shift registering signal, the shift registering signal generated by the next shift registering unit, and an enable signal ENBV. The logic gate 111 generates a logic signal V110 and outputs the logic signal V110 to an input terminal of the buffer 111. The buffer 111 outputs the logic signal V110 to generate a corresponding driving signal.
According to the circuit structure of the scan driving device 1 of FIG. 1, each shift registering unit requires one buffering output unit for generating a corresponding driving signal S1˜SN. When the buffering output units 111-11N use the buffers 111 with large driving capability, the area occupied by the buffers 111 is increased. Thus, if the display panel is designed with narrow borders, each buffering output unit in FIG. 1 would not be able to use a buffer with large driving capability due to the area limitations.